To see it in action, create an account on that goathack, or observe the friends list of user "testc". The relevant line in ljconfig.pl:
@INITIAL_FRIENDS = qw(news evan);
(For this LiveJournal installation, I recommend at least: qw(news lj_maintenance).)
Some of the discussion about mandatory friends raised some good issues.
My question to you: how to we, as the people who run the site, address everyone at once?
For example, the site will need to go down for a few hours to do the conversion to clustering, and we'd prefer to warn everyone in advance.